This application claims the benefit of Korean patent application No. 1520/1999, filed Jan. 19, 1999, which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a TFT-LCD (Thin Film Transistor Liquid Crystal Display) driver, and more particularly, to a TFT-LCD driver that consumes less power.
2. Background of the Related Art
FIG. 1 is a block diagram of a related art TFT-LCD driver, and FIG. 2 is a block diagram of a controller for the related art TFT-LCD driver.
Referring to FIG. 1, a related art TFT-LCD includes a TFT-LCD panel 11 having a plurality of gate bus lines and source bus lines, with TFT""s (switching devices) formed thereon. Capacitors are formed by injection of a liquid crystal material into a space between an upper plate and a lower plate of the TFT-LCD panel 11, to form an array of liquid crystal cells. A gate driver IC (Integrated Circuit) 12 is on a left side of the TFT-LCD panel 11 and supplies driving voltages to the gate bus lines in succession to turn the TFT""s on and off. A source driver IC 13 is on an upper side of the TFT-LCD panel 11 and sequentially supplies video signal voltages to the source bus lines in the TFT-LCD panel 11, to apply data voltages to each liquid crystal cell, with the data voltages passing through the turned-on TFT""s. A controller 14 provides control signals required for the gate driver IC 12 and the source driver IC 13.
As shown in FIG. 2, the controller 14 includes column/row control programming units 21 and 22 for receiving external data, and a pixel logic/timing generator 23 with a data buffer for converting outputs from the column/row control programming units 21 and 22 into control signals required for the gate driver IC 12 and the source driver IC 13
The operation of the related art TFT-LCD driver will be explained below.
The controller 14 generates sequential control signals for providing row addresses for received external data, provides the control signals to the gate driver IC 12, and provides digital R, G, B (Red, Green and Blue) data for row addresses to the source driver IC 13 The gate driver IC 12 supplies sequential driving voltages to the gate bus lines in the TFT-LCD panel 11, to sequentially turn on the TFT""s for the row addresses. Then, the source driver IC 13 receives the digital R, G, B data from the controller 14, converts the digital R, G, B, data into analog voltages, and supplies the analog voltages to the source bus lines in the TFT-LCD panel 11. The analog voltages are stored in capacitors in a liquid crystal cell array in the TFT-LCD panel 11 after passing through the TFT""s, which are turned on by the gate driver IC 12. As shown in FIG. 1, voltages stored in each liquid crystal cell in the TFT-LCD panel 11 are charged as either (+) or (xe2x88x92) in an alternate manner. The (+) voltage is VDD-VCOM, the (xe2x88x92) voltage is VCOM-Vss, and VCOM is approximately xc2xd(VDD+VSS).
However, the related art TFT-LCD driver has high power consumption due to the TFT-LCD panel and the source driver IC, because capacitors on data lines in a column direction are charged every time a row is addressed, as the liquid crystal cells in the TFT-LCD panel are alternately charged to (+) or (xe2x88x92) for every frame in sequential row addressing.
Accordingly, the present invention is directed to TFT-LCD driver that substantially obviates one or more of the problems due to limitations and disadvantages of the related art
An object of the present invention is to provide a TFT-LCD driver which consumes less power when driving a source driver IC and the TFT-LCD.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, in one aspect of the present invention there is provided a TFT-LCD driver including a TFT-LCD panel having a plurality of gate bus lines, a plurality of source bus lines, a plurality of TFT""s, and a plurality of liquid crystal cells corresponding to the plurality of TFT""s, a gate driver integrated circuit for supplying driving voltages to the gate bus lines to turn the TFT""s on and off, a source driver integrated circuit for sequentially supplying analog voltages to the source bus lines so as to input analog voltages to the plurality of liquid crystal cells through the turned-on TFT""S, and a controller for providing control signals to the gate driver integrated circuit and the source driver integrated circuit, wherein the analog voltages supplied from the source driver integrated circuit to the TFT-LCD panel have the same polarity at least twice in sequence, wherein the source driver integrated circuit drives the TFT-LCD panel using one of a dot inversion method and a pixel inversion method.
In another aspect of the present invention there is provided a liquid crystal display including an upper plate, a lower plate facing the upper plate, a plurality of gate bus lines and a plurality of source bus lines on the lower plate, thin film transistors formed at intersections of the gate bus lines and the source bus lines, a liquid crystal cell capacitor array formed at locations corresponding to the thin film transistors between the upper plate and the lower plate, a gate driver circuit for turning the thin film transistors on and off, a source driver circuit for supplying analog voltages to the source bus lines, wherein the analog voltages are stored in the liquid crystal cell capacitor array through the thin film transistors, and a controller for providing control signals to the gate driver circuit and the source driver circuit, wherein analog voltages outputted from the source driver circuit have the same polarity at least twice in a row, and wherein the source driver circuit drives the liquid crystal display using one of a dot inversion method and a pixel inversion method.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.